Manually controllable coded track circuit signaling system



Jam W, 1950 R. M. GlLsoN MANUAL-LY CONTROLLABLE CODED TRACK CIRCUIT SIGNALNG SYSTEM Filed sept. so, 1947 INVENTOR.

HIS ATTORNEY Patented Jan. l?, 195@ UNITED STATES;

ENT OEFCE MANUALLY CQN'IROLLABLE CODED TRACK CIRCUIT SIGNALING SYSTEM Application September 30, 1947 SerialNo. '776,995V

1 Claim.

My inventiony relates to coded track circuits for railway signaling systems of a type which may be` deenergized, and particularly to improved means for insuring proper operation of such a system under varying conditions of ballast resistance and track battery Voltage.

It. has heretofore been proposed in such sys-` tems to provide a series approach relay atI the exit end of each track section which is connected in series with the battery from which energyy is supplied to the track circuit. The lighting oi signals and the control of directional stick relays are governed by this relay, so that when a train is approaching a signal, the approach relay Willoperate to supply energy to the lamp of the signal and will also pick up the directional stick relay to clear the signal in the rear of the train after the train has passed out of the track section.

Diiiiculty may be encountered in such arrangements because of variation in ballast resistance and inthe voltage of the track battery.

If the equipment is adjusted to operate toprovide adequate approach lighting of a signal under conditions of high ballast resistance and low battery-voltage, then under conditions of low ballast resistance and high battery voltage the approach relay may operate without a, train occupying the track section and thus cause improper energization of the associated directional stick relay as well as improper lighting of the lamps of the associated signal.

Accordingly, an object of my invention is to provide improved means of the type described which is arranged so that under varying conditions of ballast resistance and track battery voltage, the approach relay will always operate to initiate lighting of the associated signal on the approach of a train within a predetermined distance of the signal, and so that when the section is not occupied the approach relay will. not operate and will not prevent release of the associated directional stick relay.

Another object of my invention is to provide anV improved arrangement of coded track circuit apparatus in which a series approach relay is employed.

A iur-'ther object of my invention. is to provide a coded track circuit railway signaling system ofV the type described in which` the voltage of the energy supplied to the track circuits of the system is maintained within selected.I limits.

Another object of my invention is to provide improved means of the type described in which they series approach relay is. prevented: from oper- 2, ating if no trainis occupying the associated track section.

A further object of my invention is to provide means responsive. to the, voltage oi a track bat..- tery and controlling the voltage of the. energy supplied from the battery to the rails,A of the associatedltracksection, the voltage responsivemeans being governed so as to be energized` from said battery only when operating conditions req-nire. A

energy to besupplied from the: battery toy the associated track section.

In practicing my invention@ provide an oyervoltage' relay which has. a winding connected acrossV the terminals oi the track battery for a track section by a circuit including contacts ci relays which operate tocomplete the circuit when the signaling system has been prepared for the movement or a train through that section. The over-voltage relayy is constructedand adjusted so that its contact remains released` for all voltages under aA predetermined Value, and so: that its contact will pick up at all voltages. over that predetermined value. A resistor is connected in series. with the approach relay and the track battery in the circuit forv supplyingenergyy to the rails of the track sectionr and this resistor is shunted by a circuit, including a back Contact of the, over-voltager relay, so that when the overvoltage relay is; released, the resistor is shunted; and when the over-voltage relay is picked up, the resistor is eectivel'y connected in series withA the track circuit'.

Other objects of my invention and features of novelty will be apparent from the following de.- scription taken in connection with the accompanying drawing.

I shall describeone form of apparatus embodying my invention and shall then poi-nt out. the novel features thereof in the claim.`

Referring to the accompanying drawing, there is shown a stretch of' railway track having track rails lI` andV 2 which are divided bythe insulated joints 3 to form separate track sections 5T and 1T; andl over which traic normally moves in. a direction indicated by the arrow, that is, from left' to right. The signals 5S and 1S, are of the well-known color light type, and each has a green lamp G, a yellow lamp Y, andi 9, red lamp R, and govern the movement of traiilc into the sections 5T and' 'I T, respectively.

The section 'iT' is assumed to be the lastl sec*- tion of a stretch ofl railway equipped with a normally deenergizedcoded track circuit, signaling system, and; the equipment; locatedat the right-hand' end of section iTy includes: a; control contact L, by which the system may be energized to prepare the system for a train movement through the stretch, from left to right, and by which the signaling system may be deenergized when its operation is not required. The contact L may be controlled in any appropriate manner, as for example, through a C. T. G system by an operator at a remote control point.

Energy for the operation of the various relays other than the track relays is furnished by suitable sources of direct current, not shown, whose positive and negative terminals are designated B and C, respectively.

The track batteries employed in this system are of the primary battery type and the voltage of the energy supplied therefrom varies between relatively wide limits throughout the life of the batteries.

In the system as shown herein, code transmitters of the pendulum type designated lllCT and TSCT are energized continuously and operate their contacts periodically at a rate of 180 or '75 times per minute, respectively, to periodically operate a transmitter relay, such as relay SCTP, by which the coded energy of the selected frcquency is supplied to the section rails.

Each code following track relay, such as TTR, governs decoding means represented by the rectangle DM, to control a code detector relay, such as relay TH, and a clear signal control relay, such as relay TD. The decoding means DM may be any of the types well-known in the art, and it is not shown in detail since it forms no part of my invention. However, it is to be understood that the relay TH will become picked up when the code following track relay TTR is operating at either the 180 code rate or the '75 code rate, and relay TD becomes picked up when and only when the code following track relay is operating at the 180 code rate. The supply of energy to the lamps of the signal TS is governed by contacts of the relays TH and TD.

A directional stick relay, such as relay TSR, is provided at each of the intermediate signal locations to provide means for permitting following traffic movements, and is governed by a contact of the approach repeater relay TAPR, which is a slow release repeater relay controlled by the code following series approach relay TAR, and also by the code detector relay TH.

The over-Voltage relay OVR has its winding connected across the terminals of the track battery STB by a circuit including front contacts of relay TH and TSR in multiple,

Explanation of the arrangement of apparatus comprising my invention will be made clear by the following description of the operation of the equipment.

In describing the operation of this equipment, it is assumed that the equipment is in its deenergized condition, as shown. It will now be assumed that the contact L is closed to prepare the system for movement of a train through the stretch from left to right, and that trafiic conditions in advance are such that control relay CR is picked up. Accordingly, a circuit is established to supply energy of 180 code frequency to the transmitting relay TCTP. This circuit is traced from terminal B, over front contact a of code transmitter I80CT, over front contact a of relay CR, over contact L in its closed position, and through the winding of relay TCTP to terminal C, and causes the contact of relay TCTP to be operated at the 180 code rate.

When contact a of relay TCTP picks up, it

establishes the circuit for supplying energy from battery TTB over the rails of section TT to winding of track relay TTR, and the contact a of relay TTR picks up. When contact a of relay TCTP releases, it interrupts the circuit traced above, and the contact of relay TTR releases. Accordingly, at this time, the coded energy supplied to the righthand end of the rails of section TT causes the contact of relay TTR to be operated at the code rate. The operation of contact a of relay TTR at the 180 code rate causes energy to be supplied through the decoding means DM to pick up the relays TH and TD. The circuit for supplying energy to the green lamp G of signal TS is now prepared by front contact c of relay TD and front contact a of relay TH, but this circuit is interrupted by front contact a of relay TAPR, which is released at this time, so that the green lamp G of the signal remains dark.

When relay TH picks up, its Contact c connects the winding of relay OVR across the terminals of the battery STB so that the relay OVR measures the voltage of the battery STB. Il the voltage of this battery exceeds a predetermined value the contact of relay OVR will pick up, and thereby cause resistance R2 to be included in the circuit for supplying energy from battery STB to the rails of section ST, but if the voltage of the battery is less than this predetermined value the contact of relay OVR will remain released and shunt resistance R2 so that this resistance is in effect removed from the circuit for supplying energy from the battery STB to the rails of section ST.

When relay TH picks up, its contact b establishes the circuit for operating the contact of transmitting relay SCTP at the 180 code rate. This circuit is traced from terminal B, over front contact a of code transmitter lCT, over front contact b of relay TH and through the winding of relay SCTP to terminal C. Accordingly, at this time the contact a of relay SCTP is picked up and released 180 times per minute.

When contact a of relay SCTP picks up, it establishes the circuit for supplying energy to the winding of relay STR over the rails of section ST. This circuit is traced from the positive terminal of battery STB, through resistor R2, through resistor RI and the winding of relay TAR in multiple, over front contact a of relay SCTP, over rail l of section ST, through the winding of relay STR, and over rail 2 of section ST tothe negative terminal of battery STB. At this time, as explained above, the circuit governed by contact a of relay OVR for shunting the resistor R2 is open or closed depending on whether or not the voltage of the battery STB is high enough to pick up relay OVR. As hereinafter explained this insures that the en ergy supplied from battery STB will not be too high or too low to produce proper operation of the relays STR and TAR.

The supply of energy through the winding of relay STR causes the relay contact to pick up, while the winding of relay TAR and resistor Ri are proportioned so that the current which. flows through the Winding of relay TAR at this time is of insufficient Value to pick up the contact of relay TAR. When contact a of relay SCTP releases, the supply of energy to the winding of relay STR is interrupted, and its contact releases. Accordingly, at this time, the coded energy sup.- plied over the rails of section ST from battery STB causes the contact of relay STR to be operated at the 180 code rate. The operation of contact a of relay STR at the 180 code rate causes Mecca@ energyV to be. supplied to the decoding means DM, and as a result, the.: contacts or relays. SH' andi 5D become. picked. up, therebyy preparing the, circuit for lighting the green lamp G of signal SS'.

Ift is nowl assumed that with. the; system energized as. described above, a train moi/ing: from left to right passes. signa-l: SS' and entersl section 5T; When the train enters section ST the supply of coded' energy to the winding of relay STR, is shunted bythe Wheels and axles of the. train and contact a of relay STR- releases and remains re'- l-eased, with the result that the supply of energy through. the` decoding means DM to relays SH. and SDfis cut oir and these relays release. When contactzb of relay SE1 releases, it interrupts` the. circuit fior the green lamp G ofv signal: SS and establishes. the circuit for the red lamp. R of the signal..

At: this time, relay SCTP continues. tov operate its: contact, supplying codedenergy fromv battery STB to. the rails of section ST' through resistor RI anclthewindingot relay 'FAR' in multiple',through resistor R2, and! also over contacta of relay OVR. it relay (DVR. is released.. Due. to. the shunting eiect ot' the Wheels and; axles of the train, the currentsupplied to therails from battery STB in creases as` the trairr approaches signal 1S. The various parts` ofthe. equipment. are. arranged and proportioned' sol thatk when the train advances Within av substantial distance of signal. 1S, asv for example, 40001ft., the value of the current which flows through the winding: or approach relay '.'AR becomes suilicient to operate the contact ofy the relay. Eachrtimecontacta of relay 'FAR picksup, energy is supplied to the slow release repeater ren lay lAPR. Accordingly, relay TJAPR- is energized, and itsY front contact` completesl the circuit including front contact a of relay 1H andlfrontcontact w of relay 1D for supplying energy to the green lampG of signal' S' so the signal S displays a proceed aspect tothe approaching train.

Additionally, whenr relay 'lAPlEtv picks up, its contact b establishes the pick-up circuit4 for the directional stick relay 'LSR'. This circuitis traced from terminal B, over iront contact b of relay 'Il-APR, over front contactv d of relay and through the winding of. relay TSR; to. terminal CJ. When relay TSR picks: up, itsicontactl c completes an additionalcircuitv to supply energy to relay from the battery STB;

When. the train passes signal 'IIS` and enters section TT, relay TTR; is: shunted and its contact `a remains released', thereby cutting off the supply of energy through the decoding meansDM'tov the relays lI-l and l'D andthese relays release. When contact c of relay 1H releases, it interrupts the supply of' energy to the green lamp G ot signalf S and establishes the circuit for supplying energy to red' lamplty of the signal. When contact d of relayv 'IH releases, a stick circuit is: established to maintain the relay ESR- energized, and istraced from terminal B1, over back contact d of relay 1H, over front contact a ci relay 'ISR and through the Winding oi relay TSR to terminal.v C'. Also, when relay 1H releases, its con-tact c inthe circuit previously traced for supplying energy to the Wind'- ingy of relay OVR` from battery STB is open, but the winding of relay OVR remains connected lacross the battery ETB over iront contact c ci relay 'ISR so the relay OVE continucstov measure 'the voltage of the battery STB.

When contact bv of relay 'IH releases, it interrupts the circuit previously traced for supplying energy coded atthe 180- code ratey tothe transmitting relayl SCTP, and establishes a circuit'v for suppliers energy coded at the 715e code rate. to relay' SCTP; This. circuit' is traced from terminal B1, over fronti contact; c of code transmitter 1SCT, over4 front; contact bl of relay' TSR, over back con,- tactb of relay 1H, and' through the winding of relay SCTP to terminal C.

As a result energy is now supplied to the rails et' section ST' at-the ZS code. rate, and since the rear' portion of the train. still occupies section; ST', theapproach; relay TAR will now4 operate its contacts at the 75 code rate, and relay 'IAPR will remain energized.

Whenthetrain under discussion vacates section ST; theremoval of the shunt decreases the value of" current supplied to the section rails from the battery STB, and. as a result the energy flowing through the' winding of relay TAR falls below. the value necessary to pick up the contact of reifa-y and itscontact remains released. Ac-v cordingly, energy is no longer supplied to relay 'IAPR over `the circuit includ-ing iront contact a ot relay TAR, and after a short time interval, the contacts of relay:l 'llAPR release.

When: Contact a of relay lA-PR releases, it interrupts thel supply of energy to the red lamp R oi signall S and it becomes extinguished. Additionally, Whe-r1v relay I-PR releases, its contact b interrupts the pick-up circuit previously traced for supplying energy toE relay t5-SR, but relay 'ISR l remains picked up by theA energy supplied over its stick circuitwhich` includes back contact d of relay IH andi trent contact ct of rel-ay TSR.

As relay 'ISR remains pickedY up when section ST is vacated, the relay SCTP continues to be operated at'- the '7-5 code rate and supplies energy from battery STB over the rails of section ST to relayV STR. When relay STR is operated by energ-y or '75' code frequency, the energy supplied through the decoding means DM is insuliicient to pick up thecontacts of relay 5D so that only relay SH' becomes picked up. When Contact a of relay. 5H picks up it prepares a circuit including back contact` a of relay 5D for supplying energy to: the yellow lamp Y of signal 5S.

When thetrain under discussion passes out of sccti'orr 'l-T, coded energy is again supplied to rel-'ay TTR' from battery 1TB by the operation of the contact of relay TC'FP. However, it is assumed that with the train` now in advance of section 1T, theV control relay CR will be released, and as a result, coded energy of 7S' code rate will be supplied to'relay 'ICTP by the circuit which is traced from terminal B, over contact a of code transmitter ISCT, over back contact a of relay CR, over contact L in its closed position, and through the Windingoi relay TCTP to terminal C.

'lhe relay TTR follows the coded energy supplied thereto; over the rails of section 1T, and as a result, the relay lI-I picks up, but relay 1D remains released.

When contact b of relay 1H picks up, the supply of coded energy to relay SCTP is changed from thel '75 code rate to the 180 code rate, and whenv contact d' of relay 'II-I picks up it interrupts the stick circuitv previously traced for relay 'ISR and relay lsRreleases; its front contacta additionally interrupting the relay stick circuit.

Energy coded atA the 1180 code rate is now sup'- plied to relay STR from battery STB, and as a result, relay SH' remains picked' up and relay SD becomes picked upto prepare the circuit for suppliyingf energy tothegreen larnp G or? signal SS'.

At this time, the winding ot relay OVR is connected across the terminals of battery' STB by the circuit'i'ncluding con-tact c oi relay When the 'train under consideration advances a substantial distance beyond section 1T, the control relay CR will again become picked up, and will cause the coded energy supplied to relay 'ICTP to be changed from the 75 code rate to the 180 code rate so that coded energy of a 1'80 code rate is supplied to relay TTR from battery TTB over the rails of section 1T. Accordingly, relay TD becomes picked up to prepare the circuit for supplying energy to the green lamp G of signal TS.

It will now be assumed that the system is to be restored to its deenergized condition. Accordingly, the control contact L is operated to its open position, interrupting the supply of energy to relay TCTP, and relay l'CTP releases and remains released, thereby cutting off the supply of energy to track relay TTR. As a result, relay TTR releases and remains released, thereby cutting off the supply oi energy through the decoding means DM to relays '5I-I and TD.

When contact b of relay 'II-I releases, it interrupts the supply of 180 code energy from the coding device IBElCT to relay SCTP, and since Contact b of relay TSR is released at this time,

energy is not supplied to relay SCTP on release of relay 'II-I, and the contact of relay SCTP releases and remains released, thereby cutting off the supply of'energy to the track relay STR from battery STB over the rails of section ST. As a result, the supply of energy to relays SH and 5D is interrupted and these relays release.

When relay TH releases, its contact d in the stick circuit previously traced for relay TSR is closed, but this circuit is interrupted by front contact a of relay TSR at this time so that relay TSR remains released. Also,- contact c of relay'TH interrupts the circuit for Connecting the winding of relay OVR across the terminals of battery STB so that when the signaling equipment is deenergized there is no load on the battery STB. The equipment is now restored to its original condition as originally described.

The proper operation of the approach relay TAR and the track relay STR is affected by the voltage of the energy supplied from the battery STB to the track rails. If the voltage of the energy supplied from the track battery to the rails of section ST is too W the track relay STR may fail to operate under conditions of low ballast resistance, while under conditions of high ballast resistance `the relay IAR may not operate to establish the circuit of the lamps of signal TS until a train approaches much closer to the signal than is desired.

On the other hand if the voltage of the energy supplied from the battery STB is too high, the relay TAR may operate continuously, irrespective of whether or not section 5T is occupied, particularly under conditions of lovv ballast resistance. If the relay TAR should operate when section 5T is vacant it would cause the lamps of signal TS to be lighted unnecessarily, thereby causing unnecessary consumption of energy.

In addition, if relay TAR should operate when section ST is vacant, the relay TSR will be energized and will maintain the supply of energy to relay SCTP and thus prevent deenergization of the coded track circuit for section 5T.

As explained above, when the signaling system for the track stretch is operating, the relay 1H is picked up and its contact d in the pick-up circuit for relay TSR is closed. If conditions are such that relay 'IAR operates even though section ST is vacant the relay TAPR will be picked 8 up and complete the pick-up circuitY for relay TSR so that relay 'ISR is picked up and closes its contact a in the relay stick circuit. Accordingly, when contact L is operated to cut olf the supply of energy to section 1T for the purpose of deenergizing the coded track circuit equipment, and the relay '1I-I releases so that its front contact d in the circuit of relay TSR is open, the relay TSR will be maintained energized by current supplied over its own contact a, and the relay contacts will remain picked up with the result that energy of 75 code frequency is supplied over front contact b ol" relay 'ISR and back contact b of relay TH to relay SCTP and it operates to supply energy from battery STB to the rails of section ST. This energy will operate relay TAR and cause relay TAPR to remain picked up to establish the circuit for supplying energy to the lamps of signal 1S, and to establish a circuit for supplying energy to relay TSR.

This system is arranged to insure proper operation of the equipment at all times regardless of variations in operating conditions. As explained above, whenever the coded track circuit equipment for section ST is required to operate the relay OVR is connected across the terminais of the battery STB. If the voltage of the battery STB is relatively low, the relay OVR will be released and its contact a will shunt the resistance R2 so that this resistance does not restrict the supply of energy from the battery STB through the winding of relay TAR and the resistance RI in multiple to the track rails and thus to relay STR. Accordingly, at this time, even though the voltage of the energy supplied from the battery is relatively low, the energy supplied from the battery will be of a value such as to be certain to operate the track relay STR and to also be certain to operate relay 'IAR when an approaching train advances within the distance of the signal TS at which it is desired to have the signal lighted. In addition, as the voltage of the battery STB is relatively low, the energy supplied from the battery to the rails of section ST, even under conditions of low ballast resistance, will not cause operation of relay TAR unless section ST is occupied.

On the other hand, if the voltage of the battery STB is relatively high, the relay OVR will be picked up and its contact a will interrupt the circuit shunting the resistance R2 so that this resistance limits the energy supplied from the battery STB. As the voltage of the battery is relatively high, the energy supplied to the track rails I and 2 of section 5T, even though limited by the resistor R2, Will be effective to operate the track relay STR even during periods in which the ballast resistance is relatively 10W. Furthermore, as the voltage of the battery STB is relatively high, the energy supplied through the relay TAR will be eiective to operatethe relay when a train advances beyond the point at which it is desired to have lighting of the signal TS initiated. In addition, even though the voltage of the battery is relatively high, the resistor R2 limits the supply of energy from the battery STB through the winding of relay TAR to a value such that even under conditions of low ballast resistance the relay 'IAR will not operate unless section ST is occupied. As relay TAR will not operate unless section ST is occupied, it Will not prevent release of relay TSR when the signaling equipment is to be deenergized.

In addition it will be seen that the circuit of relay OVR is established as soon as the relay 1H picks up so that as soon as conditions require energy to be supplied from battery ETB the relay OVR is connected across the terminals of the battery. Furthermore, the circuit of the relay OVR is maintained until after the relay TSR releases so that when the equipment is being deenergized the relay OVE, prevents improper operation of relay 'IAR as long as relay 'ISR remains picked up so that there is no possibility that relay 1SR will fail to release because of improper operation of relay TAR.

Although I have herein shown the arrangement of apparatus embodying my invention as employed in a normally deenergized coded track circuit signaling system arranged for a single direction of train movement, it will .be apparent to those skilled in the art that my invention is also applicable to other railway signaling systems, especially normally deenergized coded track circuit signalling systems arranged for two direction operation.

Although I have herein shown and described only one form of railway signaling apparatus ernbodying my invention, it is to be understood that various changes and modifications may be made therein within the scope of the appended claim without departing from the spirit and scope of my invention.

.Having thus described my invention, what I claim is:

In a coded track circuit signaling system, in combination, a stretch of railway track divided into a plurality of track sections including a first and a second section through which trafc moves in the order. named, each of said track sections having at the entrance end thereof a code following track relay operated by coded energy supplied over the section rails from the exit end of the section, means for at times supplying coded energy to the rails of said second section at the exit end thereof, a code detecting relay which is Ipicked up in response to operation of the track relay for said second section, a signal governing movement of traffic from said rst section into said second section, said signal including a lamp. a track battery the voltage of which varies a substantial amount during the life of the battery, a code following approach relay, a transmitting relay effective when rendered active to recurrently connect said battery and the winding of said approach relay in series across the rails of said rst section at the end thereof adjacent said second section, said approach relay being proportioned so that during normal battery voltage conditions the approach relay does not respond to energy of the value supplied from said battery through the relay winding to the track rails when said rst section is unoccupied and is rendered operative only on the increase in current supplied through the relay winding under predetermined conditions of occupancy of said first section, a slow release approach repeater relay energized in response to operation of said approach relay, a directional stick relay having a pick-up circuit including front contacts of said approach repeater and code detecting relays and having a stick circuit including its own front contact and a back contact of said code detecting relay, means for rendering said transmitting relay active when said code detecting relay is picked up and also when said code detecting relay is released provided said directional stick relay is picked up, an overvoltage relay connected across the terminals of said track battery when said directional stick relay or said code detecting relay is picked up, said overvoltage relay having a contact which is picked up when and only when the voltage of said battery exceeds a predetermined value, and means effective only when said overvoltage relay is picked up for including a resistance in the circuit through which energy is supplied from said track battery through the approach relay to the rails of said first section.

ROBERT M. GILSON.

REFERENCES CITED The following references are of record in the le of this patent:

UNITED STATES PATENTS Number Name Date 2,135,548 Willing Nov. 8, 1938 2,344,573 Van Horn Mar. 21, 1944 

